feat: autoload plugins that are located in `@*/prettier-plugin-* (#5945)

* add tests

* implement the feature

* update docs

* update changelog

* typo

CHANGELOG.unreleased.md

@@ -143,3 +143,5 @@ Examples:
   (a?.b[c]).c();
   let value = /** @type {string} */ (this.members[0]).functionCall();
   ```
+
+- CLI: Plugins published as a scoped NPM package (e.g.: `@name/prettier-plugin-foo`) are now automatically registered ([#5945] by [@Kocal])

docs/plugins.md

@@ -11,7 +11,9 @@ Plugins are ways of adding new languages to Prettier. Prettier's own implementat
 
 ## Using Plugins
 
-Plugins are automatically loaded if you have them installed in the same `node_modules` directory where `prettier` is located. Plugin package names must start with `@prettier/plugin-` or `prettier-plugin-` to be registered.
+Plugins are automatically loaded if you have them installed in the same `node_modules` directory where `prettier` is located. Plugin package names must start with `@prettier/plugin-` or `prettier-plugin-` or `@<scope>/prettier-plugin-` to be registered.
+
+> `<scope>` should be replaced by a name, read more about [NPM scope](https://docs.npmjs.com/misc/scope.html).
 
 When plugins cannot be found automatically, you can load them with:
 
@@ -33,7 +35,7 @@ When plugins cannot be found automatically, you can load them with:
   });
   ```
 
-Prettier expects each of `pluginSearchDirs` to contain `node_modules` subdirectory, where `@prettier/plugin-*` and `prettier-plugin-*` will be searched. For instance, this can be your project directory or the location of global npm modules.
+Prettier expects each of `pluginSearchDirs` to contain `node_modules` subdirectory, where `@prettier/plugin-*`, `@*/prettier-plugin-*` and `prettier-plugin-*` will be searched. For instance, this can be your project directory or the location of global npm modules.
 
 Providing at least one path to `--plugin-search-dir`/`pluginSearchDirs` turns off plugin autoloading in the default directory (i.e. `node_modules` above `prettier` binary).
 

src/common/load-plugins.js

@@ -95,7 +95,11 @@ function loadPlugins(plugins, pluginSearchDirs) {
 
 function findPluginsInNodeModules(nodeModulesDir) {
   const pluginPackageJsonPaths = globby.sync(
-    ["prettier-plugin-*/package.json", "@prettier/plugin-*/package.json"],
+    [
+      "prettier-plugin-*/package.json",
+      "@*/prettier-plugin-*/package.json",
+      "@prettier/plugin-*/package.json"
+    ],
     { cwd: nodeModulesDir }
   );
   return pluginPackageJsonPaths.map(path.dirname);

tests_integration/__tests__/plugin-resolution.js

@@ -21,6 +21,15 @@ describe("automatically loads '@prettier/plugin-*'", () => {
   });
 });
 
+describe("automatically loads '@<name>/prettier-plugin-*'", () => {
+  runPrettier("plugins/automatic", ["file.txt", "--parser=foobar"]).test({
+    stdout: "foobar+contents" + EOL,
+    stderr: "",
+    status: 0,
+    write: []
+  });
+});
+
 describe("automatically loads 'prettier-plugin-*' from --plugin-search-dir (same as autoload dir)", () => {
   runPrettier("plugins/automatic", [
     "file.txt",
@@ -47,6 +56,19 @@ describe("automatically loads '@prettier/plugin-*' from --plugin-search-dir (sam
   });
 });
 
+describe("automatically loads '@<name>/prettier-plugin-*' from --plugin-search-dir (same as autoload dir)", () => {
+  runPrettier("plugins/automatic", [
+    "file.txt",
+    "--parser=foobar",
+    "--plugin-search-dir=."
+  ]).test({
+    stdout: "foobar+contents" + EOL,
+    stderr: "",
+    status: 0,
+    write: []
+  });
+});
+
 describe("automatically loads 'prettier-plugin-*' from --plugin-search-dir (different to autoload dir)", () => {
   runPrettier("plugins", [
     "automatic/file.txt",

tests_integration/plugins/automatic/node_modules/@user/prettier-plugin-foobar/index.js

@@ -0,0 +1,25 @@
+"use strict";
+
+const prettier = require("prettier/local");
+const concat = prettier.doc.builders.concat;
+
+module.exports = {
+  languages: [
+    {
+      name: "foobar",
+      parsers: ["foobar"],
+      extensions: [".foobar"]
+    }
+  ],
+  parsers: {
+    foobar: {
+      parse: text => ({ text }),
+      astFormat: "foobar"
+    }
+  },
+  printers: {
+    foobar: {
+      print: path => concat(["foobar+", path.getValue().text])
+    }
+  }
+};

tests_integration/plugins/automatic/node_modules/@user/prettier-plugin-foobar/package.json

@@ -0,0 +1 @@
+{}